Faculty Bibliography

BACKGROUND:The prognostic significance of histology in ileal pouch-anal anastomosis (IPAA) remains unclear. The aim of this study was to evaluate if histologic variables are predictive of IPAA clinical outcomes and healthcare utilization. METHODS:This was a retrospective cohort study of patients with IPAA undergoing surveillance pouchoscopy at a tertiary care institution. Pouch body biopsies were reviewed by gastrointestinal pathologists, who were blinded to clinical outcomes, for histologic features of acute or chronic inflammation. Charts were reviewed for clinical outcomes including development of acute pouchitis, chronic pouchitis, biologic or small molecule initiation, hospitalizations, and surgery. Predictors of outcomes were analyzed using univariable and multivariable logistic and Cox regression. RESULTS:A total of 167 patients undergoing surveillance pouchoscopy were included. Polymorphonuclear leukocytes (odds ratio [OR], 1.67), ulceration and erosion (OR, 2.44), chronic inflammation (OR, 1.97), and crypt distortion (OR, 1.89) were associated with future biologic or small molecule initiation for chronic pouchitis. Loss of goblet cells was associated with development of chronic pouchitis (OR, 4.65). Pyloric gland metaplasia was associated with hospitalizations (OR, 5.24). No histologic variables were predictive of development of acute pouchitis or surgery. In an exploratory subgroup analysis of new IPAA (<1 year), loss of goblet cells was associated with acute pouchitis (OR, 14.86) and chronic pouchitis (OR, 12.56). Pyloric gland metaplasia was again associated with hospitalizations (OR, 13.99). CONCLUSIONS:Histologic findings may be predictive of IPAA outcomes. Pathologists should incorporate key histologic variables into pouchoscopy pathology reports. Clinicians may need to more closely monitor IPAA patients with significant histologic findings.

Background: In ulcerative colitis (UC), endoscopic improvement, defined as a Mayo Endoscopic Score (MES) of 0 or 1, is a target of treatment. The aim of our study was to evaluate the risk of clinical relapse between patients with an MES of 0 or 1 and determine if histologic activity using the Robarts Histopathologic Index (RHI) was predictive of clinical relapse. Methods: UC patients with an MES score of 0 or 1, no prior colectomy, and at least 1 year of outpatient follow-up after colonoscopy were included. Demographic, clinical characteristics, and clinical relapse were retrospectively collected. Biopsy specimens were read by a gastrointestinal pathologist. Primary outcome was defined as a composite of relapse requiring change in medical therapy, new steroid use, UC-related hospitalization, and/or colectomy. Results: Four hundred and forty-five UC patients were identified. Ninety-five percent of patients with MES 0 were in histologic remission by the RHI whereas only 35% of patients with MES 1 were in histologic remission. Twenty-six percent of patients experienced a clinical relapse; patients with MES 1 or RHI > 3 were significantly more likely to relapse (P < .01) compared to patients with MES 0 or RHI ≤ 3. When patients were stratified into 4 groups (MES 0, RHI ≤ 3; MES 0, RHI > 3; MES 1, RHI ≤ 3; MES 1, RHI > 3) and adjusted for age and sex, RHI > 3 was predictive of relapse (P = .008). Conclusions: UC patients with endoscopic improvement have a high rate of clinical relapse over time. Histologic activity is a predictor of clinical relapse.

Colorectal signet ring cell carcinoma is a rare type of colon cancer. Early diagnosis remains challenging because of nonspecific colonoscopy findings, such as diffuse circumferential thickening, stricture, and ulcerations, and the potential absence of typical pathological features in the initial biopsy sample. In this article, we report a 41-year-old man with ulcerating rectosigmoid stricture in the rectosigmoid colon with inconclusive histology. Subsequently, the patient developed small bowel obstruction and was diagnosed with stage 4 colorectal signet ring cell carcinoma with peritoneal carcinomatosis.

Introduction: Signet ring cell carcinoma accounts for about one percent of all colorectal cancers. It is an aggressive subtype of adenocarcinomas with the tendency for intramural spread and peritoneal carcinomatosis. Here, we reported a middle-aged male with circumferential colonic stenosis and inconclusive histology, found to have stage 4 colorectal signet ring cell carcinoma (SRCC). Case Description/Methods: A 41-year-old male without significant past medical history was referred to a gastroenterology clinic with bright red blood per rectum. Colonoscopy showed ulcerative rectosigmoiditis with rectal bleeding, and there was stricture in the rectum, in the recto-sigmoid colon, and from anus to descending colon (Figure A). Biopsy was obtained from the stricture. The pathology revealed granulation tissue and abundant fibrinopurulent exudate showing small clusters, and individual atypical cells stained positive for CDX-2 immunostain. Unfortunately, the patient subsequently lost follow-up. Three months later, the patient was hospitalized for small bowel obstruction. CT showed markedly enlarged heterogeneous and edematous rectum, an abnormal mass within the posterior pelvis/rectum, retroperitoneal and pelvic lymphadenopathy with thickening and nodularity of the peritoneum. Biopsy was obtained from an inguinal lymph node with histological examination showing metastatic adenocarcinoma composed of poorly cohesive signet-ring cells (Figure B). Immunostains revealed that the neoplastic cells were strongly and diffusely positive for CDX2 and CK20 while negative for CK7, confirming a colorectal primary. Accordingly, the diagnosis of colorectal signet ring cell carcinoma was made.
Discussion(s): The colonoscopic findings of colorectal SRCC could be nonspecific as diffuse circumferential thickening, stricture, or ulcerations. Typical pathological features may not appear on the initial biopsy sample. Immunohistochemical testing could help increase diagnostic yield and early identification of cancer cells. Our case hallmarked the importance of close follow-up for abnormal diffuse stricture and ulcerations in the colorectal area. These lesions may need to be rebiopsied, co-screened with abdominal imaging, and undergo an immunohistochemical investigation to characterize pathology further

Inflammatory bowel disease (IBD) is characterized by dysregulated intestinal immune responses. Using mass cytometry (CyTOF) to analyze the immune cell composition in the lamina propria (LP) of patients with ulcerative colitis (UC) and Crohn's disease (CD), we observed an enrichment of CD4⁺ effector T cells producing IL-17A and TNF, CD8⁺ T cells producing IFNγ, T regulatory (Treg) cells, and innate lymphoid cells (ILC). The function of these immune cells is regulated by store-operated Ca²⁺ entry (SOCE), which results from the opening of Ca²⁺ release-activated Ca²⁺ (CRAC) channels formed by ORAI and STIM proteins. We observed that the pharmacologic inhibition of SOCE attenuated the production of proinflammatory cytokines including IL-2, IL-4, IL-6, IL-17A, TNF, and IFNγ by human colonic T cells and ILCs, reduced the production of IL-6 by B cells and the production of IFNγ by myeloid cells, but had no effect on the viability, differentiation, and function of intestinal epithelial cells. T cell-specific deletion of CRAC channel genes in mice showed that Orai1, Stim1, and Stim2-deficient T cells have quantitatively distinct defects in SOCE, which correlate with gradually more pronounced impairment of cytokine production by Th1 and Th17 cells and the severity of IBD. Moreover, the pharmacologic inhibition of SOCE with a selective CRAC channel inhibitor attenuated IBD severity and colitogenic T cell function in mice. Our data indicate that SOCE inhibition may be a suitable new approach for the treatment of IBD.

BACKGROUND AND AIMS:Bacterial swarming, a collective movement on a surface, has rarely been associated with human pathophysiology. This study aims to define a role for bacterial swarmers in amelioration of intestinal stress. METHODS:We developed a polymicrobial plate agar assay to detect swarming and screened mice and humans with intestinal stress and inflammation. From chemically induced colitis in mice, as well as humans with inflammatory bowel disease, we developed techniques to isolate the dominant swarmers. We developed swarm-deficient but growth and swim-competent mutant bacteria as isogenic controls. We performed bacterial reinoculation studies in mice with colitis, fecal 16S, and meta-transcriptomic analyses, as well as in vitro microbial interaction studies. RESULTS:We show that bacterial swarmers are highly predictive of intestinal stress in mice and humans. We isolated a novel Enterobacter swarming strain, SM3, from mouse feces. SM3 and other known commensal swarmers, in contrast to their mutant strains, abrogated intestinal inflammation in mice. Treatment of colitic mice with SM3, but not its mutants, enriched beneficial fecal anaerobes belonging to the family of Bacteroidales S24-7. We observed SM3 swarming associated pathways in the in vivo fecal meta-transcriptomes. In vitro growth of S24-7 was enriched in presence of SM3 or its mutants; however, because SM3, but not mutants, induced S24-7 in vivo, we concluded that swarming plays an essential role in disseminating SM3 in vivo. CONCLUSIONS:Overall, our work identified a new but counterintuitive paradigm in which intestinal stress allows for the emergence of swarming bacteria; however, these bacteria act to heal intestinal inflammation.

Purpose: To carry out a large international validation of how dose prediction quality translates to plan quality in a radiotherapy knowledge-based planning (KBP) process.
Method(s): We collected dose predictions for head-and-neck cancer radiotherapy from 21 different research groups internationally who participated in the OpenKBP Grand Challenge. Each research group used the same training dataset (n=200) and validation dataset (n=40) to develop their methods. These methods predicted dose on a testing dataset (n=100), and those 2100 unique dose predictions were input to a previously published plan optimization method to generate 2100 treatment plans. The predictions and plans were compared to the ground truth dose via: (1)error, the mean absolute voxel-by-voxel difference in dose; and (2) quality, the mean and maximum deviation across 23 dose-volume histogram (DVH) criteria.
Result(s): The range in median prediction error among the top 20 methods was 2.3Gy to 12.0Gy, which was 6.8Gy wider than the range in median plan error of 2.1Gy to 5.0Gy. One method also achieved significantly lower prediction error (P<0.05; one-sided Wilcoxon test) than all the other methods, however, it generated plans with error that was not significantly lower than 28.6% of the other methods. Additionally, predicted dose was consistently lower quality than plan dose. Half (n=1050) of all predictions and plans had an average deviation that was 0.1Gy worse and 0.8Gy better than the ground truth dose, respectively. Similarly, half of all predictions had a maximum deviation that was 3.7Gy worse than the ground truth dose, which was 1.0Gy worse than half of all plans.
Conclusion(s): Many dose prediction methods can achieve low error, however, optimization often improves upon the predictions and eliminates significant differences between prediction methods. Thus, it is critical that we improve the optimization stage in KBP to get better utility out of the existing high-quality dose prediction methods

Multiplexed immunohistochemical techniques give insight into contextual cellular relationships by offering the ability to collect cell-specific data with spatial information from formalin-fixed, paraffin-embedded tissue sections. We established an automated sequential elution-stripping multiplex immunohistochemical assay to address two controversial scientific questions in the field of hepatopathology: 1) whether epithelial-to-mesenchymal transition or mesenchymal-to-epithelial transition occurs during liver injury and repair of a chronic liver disease and 2) if there is a stromal:epithelial relationship along the canals of Hering that would support the concept of this biliary structure being a stem/progenitor cell niche. Our 4-plex assay includes both epithelial and mesenchymal clinical immunohistochemical markers and was performed on clinical human liver specimens in patients with primary biliary cholangitis. The assay demonstrated that in each specimen, co-expression of epithelial and mesenchymal markers was observed in extraportal cholangiocytes. In regard to possible mesenchymal components in a stem cell niche, 82.3% ± 5.5% of extraportal cholangiocytes were intimately associated with a vimentin-positive cell. Co-expression of epithelial and mesenchymal markers by extraportal cholangiocytes is evidence for epithelial to mesenchymal transition in primary biliary cholangitis. Vimentin-positive stromal cells are frequently juxtaposed to extraportal cholangiocytes, supporting an epithelial:mesenchymal relationship within the hepatobiliary stem cell niche. Our automated sequential elution-stripping multiplex immunohistochemical assay is a cost-effective multiplexing technique that can be readily applied to a small series of clinical pathology samples in order to answer scientific questions involving cell:cell relationships and cellular antibody expression.

INTRODUCTION: Hepatitis D virus, also known as the 'Delta virus' is a defective virus that requires hepatitis B virus for infection. About 257-291 million people are chronically infected with HBV worldwide, and of those up to 20 million had experienced HDV infection. We present unusual case with histological, serological, virological evidences of chronically active HDV infection which was initially thought to be medication induced. CASE DESCRIPTION/METHODS: A 34 yo M with PMH of Chronic hepatitis B infection diagnosed in 2013 has been on Tenofovir Disoproxil Fumarate (TDF) x4 years. After getting switched from TDF to Tenofovir Alfenamide (TAF) he had a rise in LFTs; Bilirubin 0.2, AST 126, ALT 327. He denied alcohol use, herbal use, recent travel or other toxic habits. On presentation, VS were within normal limits and complete physical examination was unremarkable. Patient was switched from TAF to TDF as it was thought to be possibly contributing to his abnormal LFTs and a complete liver disease work up was obtained. Laboratory testing revealed TB 0.9, AST 134, ALT 386, ALP 49, INR 1.1, Hepatitis B sAg+, sAb-, eAg-, eAb-, HBV DNA non detected, HDV Ag-, HDV Ab+, HDV PCR 133,000. Ultrasound showed hepatic steatosis. Despite switching back to TDF his LFTs remained elevated. Therefore, liver biopsy was performed showing features of portal and lobular inflammation consistent with hepatitis B & D infection and fatty liver disease. He was started on Pegylated Interferon-alpha treatment, and post-treatment, his LFTs have normalized, AST-28, ALT-43, HDV PCR 1050 IU/ml. DISCUSSION: HDV is a single stranded RNA that is composed of an outer HBsAg lipoprotein envelope, inner ribonucleoprotein structure and is complexed with the HDV encoded antigen. It can present as either acute HBV-HDV coinfection, acute HDV superinfection of a chronic HBV carrier, or as chronic HDV infection. HDV infection causes more severe viral hepatitis, increases risk of developing cirrhosis and hepatocellular carcinoma in comparison to HBV monoinfection. Prevalence of HDV Ab is highest in Africa, Turkey, Mongolia, Moldova, sex workers, IV drug users, HCV, HIV, etc. Clinically HDV infection manifests from asymptomatic carrier state to acute liver failure. Diagnosis of HDV is done with serologic testing. INF-a has been the only proven antiviral treatment against HDV. SVR to therapy, which is measured as undetectable serum HDV RNA levels is at around 25%. Although rare HDV should part of a differential diagnosis in all patients with HBV infection

BACKGROUND:Mucinous adenocarcinoma (MAC) is a distinct type of colorectal cancer (CRC) associated with poor response to treatment and poorer prognosis. MAC is diagnosed by WHO definition when the extracellular mucin is more than 50% of the lesion. We aimed at assessing the gene expression profiles of the CRCs with any mucinous features (> 5%) in a retrospective study. METHODS:The data of a 50-gene next generation sequencing (NGS) panel of 166 CRCs was analyzed and the gene mutational profile with morphologic features was correlated. RESULTS:We identified the different genetic mutation profiles between CRCs with and without mucinous component, but noticed a similar genetic profile between MACs and CRCs with mucinous component, irrespective of the percentage (if mucinous component more than 5%). The different genetic mutation profile related to MSI status was also identified between two groups of tumors. The most frequent mutations in CRCs with mucinous component are KRAS (28/49, 57.1%) and BRAF (19/49, 38.7%), PIK3CA (16/49, 32.6%), followed by APC (12/49, 24.5%) and TP53 (11/49, 22.5%). The combined mutation frequency of the two key factors in the EGFR signaling pathway, KRAS and BRAF, in the CRCs with and without mucinous component is 95.9 and 52.1%, respectively. CONCLUSIONS:The dysregulation of EGFR pathway plays a critical role in the development of CRCs with mucinous component, irrespective of the percentage. The result suggested that the current cut off of 50% mucin component to define mucinous adenocarcinoma might be challengeable.